Apparatus for controlling chemical reactions



July 15, 1941` E. J. HouDRY 2,248,993

ArPARATUs FOR coNTRoLLme caEMicAL REACTIONS original Filed May's, 19:56

l'NyENToR v EuncNEdHnuom Patented July .15, y1941 APPARATUS-FOR CONTROLLNG CHEMlCAL REACTIONS Eugene J. Houdry, Ardmore, Pa., assigner toHondry Process Corporation, W

ilmington, Del.,

a'col'poratlon of Delaware Original application May 8, 1936, Serial No.78,542. y Divided and this application February 9, y1939.

Serlal No. 255,459

z claims. (cl. 234288) This invention relates apparatus for controllingchemical reactions and is a division of i the invention set forth in mycopending applicaaspects of the invention wasilled on April 4.

- 1939. More particularly, it concerns temperature control of exothermicor endothermic reactions eileoted in the presence or with the aid ofcontact masses.

One object of the invention is to adjust the temperature of a gaseousstream by its passage in heat exchange relation with the reaction zonebefore being admitted to the contact mass. Another object is to effectheat exchange chiefly by radiation to or from the exterior of thereaction zone. Still another object is to maintain substantiallyconstant temperature throughout the reaction zone. Still other objectswill be ap- 'parent from the detailed description which follows.

While the invention is capable of rather general application, it is ofparticular value in controlling exothermic reactions, as for example,combustion reactions resulting from treatment of' regeneration fumesfrom catalytic converters after the manner set forth in my aforesaidcopending and parentapplication to prepare the fumes for industrial use,as indicated, for example, in the copending application of myself andRQS. Vose, Serial No; 58,858, led January 13, 1936 (Patent No. 2,167,655issued August l', 1939).

Concrete embodiments of the invention are disclosed inthe acompanyingdrawing, in which:

Fig. `1 is a vertical sectional view through a converting unit, thesection being made substantially on the line I-l of Fig. 2;

Fig. 2 is a transverse sectional view substantially on the line 2-2 ofFig. l; and

Fig. 3 is a fragmentary or left half section Fig. l, showing amodification.

The apparatus provides a reaction zone for the desired contact orcatalytic mass M. deilned by a tubular member or casing l havingscrewthreaded connection with a lower header 6 and welded to an upperheader member 1. An outlet pipe 6 leads from the upper end of thereproducts, for example, neutral heated regeneration fumes which may beconducted away to suitable apparatus (not shown) for further treatmentof any known or desired type. When the duid issuing from line l is inertburned combustion fumes, the treatment may lbe utilization of kinetic orheat energy in those fumes.

The gaseous material to be treated may enter the lower end of thereaction zone by an inlet pipe I0 extending through header 6. To insurethe stream entering the zone at the proper temperature and also to givea measure of control of the reaction, thestream, prior to its admissionto pipe I0, may be brought into extended heat exchange with 4theexterior of the reaction zone, but such heat exchange is conned,primarilyto radiation. By preference, the gaseous stream picks up heatprogressively as it iscaused to traverse the length or depth of theelongate reaction zone. As indicated, feed conduit I I may be formed ina coil I Ia which encircles the reaction zone throughout its lengthfrom' outlet end 8 to inlet end l0.' The turns of coil Ila may A wire,cotter pin, or other member is inserted through the rods as at I2c toretain them. in place. To control the quantity of heat absorbed orradiated by coil IIa per unit of length of'the reaction chamber. and toprovide for expansion of the stream, coils I la m'ay be changed in shapeor increased in size as they approach 'inlet I0,

' this change or increase being eiected in stages,

by the use of sections of -plpe of increased diameter or increasedsurface presented 'to casing 5, or gradually and progressively asindicated vin Fig. l. The lower end of coil .Ila maybe joined to inletlconduit -Ill by a suitable connection I3. To prevent loss of heatfromthe unit,l an outer casing Il, which is preferably in sections to allowfor the pipe connections II and I3. is secured to upper and lowerheaders l. and 6 in any suitable manner, as by seating the lower end inan annular recess 6a in lower'header '6, while the upper end is attachedor clamped to header 1 as by a split ring I5. A layer of heat'vinsulating material I6 may be applied to the entire exterior of theunit.

Progressive exchange of heat by radiation may be eiected between :thefeed Vand the. reaction I o zone in other ways. If it isnot desired tochange the size or shape of the conduit making up coil Ila, a conduit ofuniform size and shape-may be utilized, but the pitch of the coil may beincreased as lower header i4 is approached by making the coils-closertogether. thereby increasing the ration chamber andrwhich enclose thecatalytic r or other contact; mass, Vthe rate of heat exchange beingcontrolled to provide accurate .temperature regulation of localizedportions of the reaction zone to offset tendencies of the latter toabsorb or radiate smaller quantities of heat as the temperature of thefluid traversing the coils approaches the temperature'of the reactionzone and its contents. Thus, provision is made for controlling increaseof the temperature of the reactants at regulated rate by increasedsurface areas, by baiiles, or by other means so as to remove or supplysubstantially equal amounts of heat from or to all parts of the reactionzone.

One exothermic reaction to which the apparatus is Well adapted is in thecombustion of car,- bon monoxide and/or oil .vapors which may bepresen-t in' regeneration 'fumes issuing from a catalytic converter forthepurpose of increasing the energy content of the fumes, which may bethereafter recovered either as kinetic energy or as heat` energy orboth, as indicated, for example, in the aforesaid copending applicationof myself and R. S. Vose. The combustion is best effected when a contactmass is employed, which may vary in character, depending upon thetemperature at which the gaseous stream enters the combustion chamber.When it entersat high temperatures, as of the order of1000" F. or more,and contains suiiicient oxygen, the contact mass may be mere inertspreading material, but preferably of a highly porous nature, so as toretain oil vapors and the like until combustion is effected, suchaspumice, kaolin, iirebrick, and other blends of silica and alumina.This material is preferably in the form of lumps, fragments, or moldedVpieces. When the gaseous stream enters the combustion zone at atemperature below 1000 F., as of the order of 900 F., the contact massmay comprise or cont-ain suitable catalytic material, such, for

example, as metallicoxides and compounds, in-

cluding thoseof copper, iron. cobalt, nickel and lead. The metals may beutilized directly, as in the form of shavings or' tuniings, or the metalor metallic compound may be in finely divided form on or incorporated insuitable. supports such as iiiert or active blends of silica and aluminaof natural or artificial origin, preferably in the form oi.' lum ns,fragments or molded pieces.

Other exnthermic reactions which may be conducted within casing 5 withthe aid of'suitable contactmass of known or desired type includesynthesis of |ammonia from nitrogen and hydrogen, hydrogenation .ofhydrocarbons and their derivatives, polymerization of hydrocarbons. andregeneration by burning of contact masses which have been vcontaminatedwith' carbonaceous, sulphur bearing o r other combustible deposits asthe result of an endothermic-or exothermic onstream reaction.

When the 'apparatus of this invention is used forlcontrollingtemperature of an endothermic reaction zone suitable fluid isadmitted tothe heat exchange coil at somewhat higher ltemperature than desired inthe reaction zone. Then the rates at which heat of reaction is suppliedto localized portions of the zone are regulated by the increasedradiating surfaces of the coil. A few typical endothermic'reactions forwhich 4this operation is used are the transformation of higher boilinghydrocarbons into lower boiling products, the dehydrogenation ofordinarily gaseous hydrocarbons, and transformation of low anti-knocknaphthas and the like into high antiknock motor fuels.-

. Suitable or desired cooling or heating medium may be added to thereactants beforeand/or after -they traverse the radiant heat exchangecoil or the like to assist in control of the radiant heat exchangebetween the coil and the reaction vessel and in regulation of thetemperature of a reactant iiuid a-s it enters the reaction Such-addition to reactants entering the carbon monoxide and hydrocarbons, acooling or heat absorbing medium such as air, or an extraneous fluidsuch as inert gases, atomized water or steam may be added by line 30 toincrease the heat absorbing capacity of the heat exchange coils throughdecrease of the temperature and/or increase of the bulk ofmaterialentering and traversing the same. Further adjustment of thetemperature and/or composition of the reactants entering casing 5 may beeffected by admitting a portion of the reactants at controlledtemperature or a suitable diluent fluid to the stream iiowing throughline I0, as by valved conduit 3|. When it i-s desired to reduce heatradiation from casing 5 lor to increase the rate of absorption ofendothermic reaction heat therein a stream of reactants or other fluidheated to the desired temperature may be added by valved line '30. Withcertain reactions, as for example, when oxidizing a stream of gasescontaining burnable components and oxygen or when treating a stream ofhydrocarbon starting material elevated temperatures may be obtained inline Il by effecting controlled combustion therein, as by addinga'suitable fuel or a controlled amount of air .to the combustion gasesor hydrocarbons as the case may be. A

The apparatus of `this invention provides. among otherimportantadvantages, a reaction vessel in which all portions of thedesired cata- 55 lytic or other contact mass are disposed at small andeven minimum distance from a heating or cooling surface maintained atpredetermined and closely regulated temperature. Thusl each portion ofthe mass has the quantum oi' reaction heat produced or absorbed by thereaction effected therein removed from or' supplied to an adjacent heatexchange surl'ace with the result that substantially constant andpredetermined temperature may be maintained in all portions of v thereaction zone.

When it is desirable to utilize a reaction zone vhaving substantialwidth as compared. to its length, the Iheat removal from or absorptionby the outer wall of the reaction chamber may be supplemented by one ormore heat exchange conduits of suitable type embedded in the con tactmass. Such conduits may be capable of introducing4 reactants into themass in addition to controlling temperature of localized portions of thesame. Advantageous types of conduits for controlling the temperature ofinterior portions of the mass by means of reactants or other heatexchange fluid are disclosed in U. S. Paten-t 1,987,933, issued January15, 1935 t0 J. W. Hai- A rison, in U. S. Patent 1,987,636, issuedJanuary 15, 1935, to T. B. Prlckett' and myself: and in U. S. Patent2,042,469, issuedJune 2, 1936 to A. Joseph.

Although this 'invention has beendescribed in I connection withregulating the temperature of reactants for the desired endothermic orexothermic reaction. it is tol be" understood that it is by no -meansvlimited to this preferred use. Suitable extraneous heat exchangeiuid,for example, mercury, inert gases, fused salts and the like' may'bepassed through the 'radiant heat exchange conduit or conduits. l'n suchinstances, connection I3 between the heat 'exchange unit and thereaction chamber will be omitted and conduits il and Il will beconnected to suitable sources for simplyinsfheat exchange fluid andreactants, respectively, while the heat exchange fluid may dischargefrom -the radiant side and end walls, a conduit spaced from'and outsideof theside walls and extending lengthwise of the 'reaction chamber,means for supplying heat exchange fluid for passage through saidconduit, said conduit being so constructed and arranged as to provideprogressively increasing heat exchange surfaces per unit of conduitlength and per unit .of reaction chamber length, said f heat exchangesurfaces facing saidside wall to transfer heat by free radiation betweensaid side wall and 'said conduit in order to regulate the temperature ofcontact material in said reaction chamber.

2. vApparatus foreifecting chemical reactions comprising a catalyticreaction chamber having side and endwa11s, acoil outside said reactionchamber, means for supplying heat exchange fluid for passage throughsaid coil, said coilbeing so constructed and arranged as to provideprogressively increasing heat exchange surfaces per unit of conduitlength and per imit of reaction chamber length, said heat exchangesurfaces facing said reaction chamber side wall to transfer heat by freeradiation between said side vwall and said coil in order to regulate thetemperature of contact material in said reaction chamber.

- EUGENE J. normar.

